Efficient turn-on Zr based metal organic framework fluorescent sensor for ultrafast detection of danofloxacin in milk samples

doi:10.21203/rs.3.rs-3130230/v1

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Efficient turn-on Zr based metal organic framework fluorescent sensor for ultrafast detection of danofloxacin in milk samples

https://doi.org/10.21203/rs.3.rs-3130230/v1

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published 14 Aug, 2023

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Metal organic framework, UiO-67 was synthesized by coordinating Zr(IV) with 4,4'-biphenyldicarboxylic acid (BPDC) ligand. Morphology and crystallinity of MOF was confirmed with FE-SEM and PXRD procedure. Danofloxacin (DANO), a veterinary antibiotic, was detected in milk by employing UiO-67 as “turn-on” fluorescent sensor. Original photoluminescent (PL) efficiency of UiO-67 sensor was enhanced on its electronic interaction with DANO molecule. Significant PL efficiency enhancement, lower detection limit 0.49 ng/mL (1.37 nM), swift detection (< 1 min), and excellent linear correlation (R²= 0.9988) indicated extraordinary sensitivity of developed MOF sensor for DANO. Selectivity and performance of sensor was unaltered in presence of interfering species and detection results were obtained under permissible variation limits. Method applied successfully for ultra-trace detection of DANO residues in milk samples.

Antibiotic

metal organic framework

photoluminescence

danofloxacin

fluorescent sensor

Zr-based MOF, UiO-67, a fluorescent sensor was synthesized by solvothermal procedure.
Developed MOF determined danofloxacin in milk samples.
Determination of danofloxacin was evaluated under co-presence of other fluoroquinolones.
Lower detection limit (0.49 ng/mL) established the developed MOF as swift sensor for danofloxacin.

Contamination of environmental resources with synthetic biomolecules above permissible levels poses a serious challenge to human health and existence. Hospital waste, live stocks, effluent of pharmaceutical industries and domestic sewage plays an important role in exaggerating this problem. Fluoroquinolone (FQ) derivatives, potential veterinary and human antibiotics, are archetypal examples of such contaminants. Fluoroquinolone antibiotics are widely used in treatment of harmful Gram + ve and Gram -ve bacterial infections[1, 2]. DANO is an important FQ used to treat respiratory problems in cattle, pigs, and poultry. Its intake by dairy cattle results in higher DANO concentrations in milk, leading to antibiotic resistance in humans[3]. Therefore, ultra-trace detection of DANO in milk is necessitated before human consumption.

Several instrumental techniques, such as electrochemistry[4], HPLC[5], capillary electrophoresis[6] and Raman spectroscopy[7], have been utilized for determining FQs traces in physiological fluids, pharmacological products and food samples. Though these methods have high efficiency, sensitivity and accuracy but majority of them possess inherent limitations such as costly instrumentation, column congestion, poor reproducibility, tedious samples pre-treatment procedures and highly skilled manpower involvement, which capped their ability for easier and swift analysis of real samples. To address such issues, sensor based techniques are introduced for qualitative as well quantitative analysis of FQs. Fluorescence spectroscopy has gained popularity as an alternative method to other techniques due to its simple and quick operational procedure, low cost, high sensitivity, selectivity and reproducibility. Recently several fluorescent probes have been developed and tested for antibiotic detection. Organic semiconductor films are most researched material involved in development of biological and chemical sensor devices[8]. Graphene oxide[9], organic dyes[10] and quantum dots[11] are other materials incorporated as fluorescent sensors to detect antibiotics. Despite being commercialized, the above conventional sensors possess reduced selectivity and sensitivity for biomolecules [12]. Organic dyes based sensors have shorter life span (about 5 min) under visible light[10]. High toxicity, complicated size and surfaces, and bi or multi-exponential decay behavior are some major drawbacks of quantum dot based sensors[11]. To overcome reported drawbacks, metal organic frameworks (MOFs) based sensors have been introduced as potential substitute to other kind of sensors[13].

MOFs are a novel category of porous, crystalline materials constructed of metal ions/clusters that function as joints and are confined by multidirectional organic ligands that act as linkers in mesh topology. Extensive growth has been made in development of new MOFs due to inherent presence of some intriguing properties like high permeability and porosity, large surface area, chirality, unsaturated co-ordination sites and H-bonding ability between analyte and framework etc [14].

MOF UiO-67 sensor was synthesized by solvothermal method using Zr metal ion and 4, 4'-diphenyl dicarboxylic acid as an organic ligand. MOF’s fluorescence efficiency enhancement upto 1616% was observed when interacted with DANO moiety. MOF’s higher aqueous stability and lower detection limit proven its high sensing capability for DANO antibiotic, making it highly suitable for practical uses.

2.1. Materials and methods

Zirconium tetrachloride (ZrCl₄), 4,4'-biphenyldicarboxylicacid (BPDC), levofloxacin (LEVO), norfloxacin (NOR), ofloxacin (OFLO), danofloxacin (DANO), ciprofloxacin (CIPRO) and lomefloxacin (LOME) of analytical standard were purchased from Sigma-Aldrich (Mumbai, India). N, N-dimethylformamide (DMF) and acetic acid were procured from Avra chemicals, India. All chemicals were of analytical ratings and utilized without further purifications. Deionised water was prepared in the lab by triple distillation process. PXRD data was obtained over range (2θ) of 2–60⁰ on an Empyrean x-rays diffractometer by using monochromated Cu-k_α radiation (λ = 1.5406Å). Perkin Elmer Fourier transform infrared spectrometer (RXIFT-IR, Japan) was used to scan FT-IR spectra in spectral range 450–4000 cm^− 1. Carl Zeiss Merlin compact equipment was used to capture FE-SEM images of gold-coated sample and EDS spectrometer was used to examine elemental analysis. Ultrasonic bath (Sarthak scientific services, India) was used for ultrasonication of sample solutions. Shimadzu RF-5301PC spectrofluorophotometer was used for PL studies. Gauss View 5.08 and Gaussian 09 software were used to carry out density functional study. Centrifuge Remi RM-12C was used for centrifugation process.

2.2 Synthesis of UiO-67

Solvothermal synthesis of UiO-67 MOF was carried out with acetic acid as modulating agent [15]. 0.5593 g (2.4 mM) ZrCl₄, 0.5814 g (2.4 mM) BPDC and 1.37 mL of acetic acid were dissolved in 30 mL DMF at room temperature around 30°C. Resulting mixture was placed in a 50 mL teflon-lined stainless steel autoclave and heated continuously in an oven at 125°C for 40 hrs. After cooling to room temperature, the white residue was washed thrice with DMF and dried in oven at 150°C for next 24 hrs.

3.1 Characterization of UiO-67

3.1.1 FT-IR

FT-IR analysis of free BPDC ligand and synthesized MOF was performed (Fig. 1). The C = O stretching vibration of carboxylic group of free ligand produced a distinct peak at 1675 cm^− 1. Absorption bands at 1654 cm^− 1 and 1590 cm^− 1 were due to asymmetric (ν_as) and symmetric (ν_s) stretch of COO⁻ groups present in UiO-67. The osseous vibration of aromatic ring (C = C) produced a strong peak at 1406 cm^− 1. A broad –OH peak of carboxylic group initially present in free ligand appearing at 3000 − 2500 cm^− 1 got shifted to new position 3403 cm^− 1 after synthesis of MOF and concurrent appearance of two new wagging vibrations at 658 and 770 cm^− 1, clearly indicating the development of Zr-O linkage in synthesized material[16, 17].

3.1.2 PXRD

The pivotal peaks in PXRD spectra of UiO-67 at 2θ = 5.74°, 6.61°, 9.34°, 11.41°, 19.58° and 30.34° mirror resembled with main peak at 5.7° and 6.6° in simulated pattern of UiO-67, already documented in literature, indicated successful formation of UiO-67[17, 18]. Sharp PXRD peaks validated the synthesized material's high crystallinity. The absence of extra peaks in observed PXRD pattern confirmed the crystalline purity of synthesized material (Fig. 2).

3.1.3 FE-SEM

FE-SEM images of UiO-67 surface at x20,000 and x30,000 magnification were used to validate the results of structural and topographical examination of synthesized MOF (Fig. 3). FE-SEM micrograph illustrated the regular, highly porous, and rounded morphology of MOF with an average particle size of 113 nm.

3.1.4 EDX and elemental mapping

EDX analysis was used to identify elements that constituted MOF material. Elemental mapping of UiO-67 confirmed the presence and distribution of zirconium (Zr), carbon (C), and oxygen (O), with percentage atomic weights (atomic ratio); 26.42% (4.87%), 51.11% (71.53%), and 22.47% (23.60%), respectively (Fig. 4). Presence of Zr metal and all elements of BPDC ligand in final structure of MOF provide strong support for successful synthesis of UiO-67.

3.2 Photoluminescence study

Stock suspension was produced by dispersing 1.0 mg finely powdered UiO-67 in 50 mL triple-distilled water and sonicated for 25 min. Aqueous stock solution (10 ppm) of each FQ antibiotic (CIPRO, NOR, LEVO, OFLO, LOME and DANO) were prepared. Aqueous diluted batches of DANO from 2.8 to 11.75 ng/mL were prepared from its stock solution. Next, 0.1 mL of UiO-67 MOF stock suspension and 2.9 mL aqueous solution of every FQ (10 ppm) were mixed together in six different vials. Fluorescence examinations of each vial were carried out. All PL spectra were recorded at excitation wavelength (λ_ex) 300 nm with slit widths 5 nm each for emission and excitation monochromators.

3.2.1 Excitation wavelength

Emission spectra of MOF’s suspension were recorded at excitation wavelengths ranging between 290 nm to 350 nm (Fig. 5a). Maximum fluorescence emission intensity was achieved at λ_ex = 300 nm. So, for subsequent studies, excitation wavelength 300 nm was selected.

3.2.2 Solvent effect

Emission spectra of MOF’s suspension were recorded in water, DMF, ethanol, acetonitrile, methanol and acetone solvents (Fig. 5b). Aqueous MOF suspension displayed highest PL intensity compared to organic solvents. Therefore, water was selected as MOF’s dispersion medium for all subsequent investigations.

3.2.3 pH effect and response time

Using 0.1 M NaOH and 0.1 M HCl solutions, basic and acidic aqueous samples of DANO having pH from 4.0 to 10.5 were prepared. 0.1 mL of UiO-67 MOF suspension was added to every sample having different pH (2.9 mL) such that resultant volume was 3 mL. PL intensity variation of MOF-DANO couple was examined over prepared pH range (Fig. 5d). Near neutral pH region, MOF-DANO couple displayed highest luminescence intensity. Thus, pH near to 7 was maintained as appropriate pH for subsequent studies.

Aqueous DANO solution (2.9 mL) and 0.1 mL of MOF stock suspension were mixed to make final volume 3 mL. Fluorescence spectra were repeatedly recorded every one min and upto 10 min. Complete PL enhancement was obtained within first one min and PL intensity remained unchanged afterward (Fig. 5c). Quick enhancement confirmed the probe's rapid sensing response.

3.2.4 Selectivity studies

PL emission spectra MOF with all FQs were obtained under optimized conditions (Fig. 6a). Addition of FQs enhanced the PL intensity of MOF suspension but maximum enhancement was obtained for MOF-DANO couple. The PL enhancement efficiency of every FQ was determined by using formula

enhancement efficiency % = [(I − I₀)/ I₀] × 100

I₀ and I are the PL intensities before and after addition of FQ. Highest PL enhancement efficiency (1616%) of MOF for DANO was achieved compared to CIPRO (49%), NOR (483%), LEVO (858%), OFLO (958%) and LOME (1072%) (Fig. 6b). Thus, UiO-67 was successfully employed as a "turn-on" fluorescence sensor for DANO.

3.2.5 Sensitivity studies

0.1 mL of UiO-67 stock suspensions was added to 2.9 mL of DANO solutions having different drug concentrations ranging from 2.8 to 11.75 nM (1-4.2 ng/mL). Fluorescence intensities were increased with increasing concentration of DANO (Fig. 7). Stern Volmer equation I/I₀ = 1 + K_SV × [DANO], was used to calculate enhancement effects. Here, I₀ and I are fluorescence intensities of UiO-67 suspension at λ_ex = 300 nm in the absence and presence of DANO, respectively. [DANO] is concentration of DANO and K_SV is Stern-Volmer constant. (I-I₀)/I₀ v/s concentration of DANO generated a linear correlation curve with R² = 0.9988 (Fig. 8). Limit of detection was calculated by using formula; LOD = 3.3 σ/m, where m stands for slope and σ for standard deviation of linear curve.

3.2.6 Interference study

Interference effect of co-presence of other FQs viz., CIPRO, NOR, LEVO, OFLO and LOME on PL intensity of DANO-MOF couple was investigated (Fig. 9). Interfering FQs were mixed in ratio 1:1 to original concentration of DANO and MOF suspension. No significant variation in PL intensity of MOF-DANO couple was noticed. Thus, presence of additional FQs did not interfere with DANO’s detection and MOF preferably couples with DANO.

3.2.7 Recyclability

After MOF’s third sensing cycle, all samples were pooled in a beaker and filtered with Whatman filter paper grade 1. Residue collected on filter paper was washed three times with triple-distilled water and dried at 80 ⁰C prior to IR and XRD examination. PL emission property of retrieved UiO-67 sensor was inspected and observed that intensity enhancement property remained intact up to third usage cycle. Morphological integrity was preserved as FT-IR and PXRD pattern of used UiO-67 remained intact, when analysed after sensing procedure.

3.3 Mechanistic study

All possible interactions between MOF and FQs were examined in order to comprehend “turn-on” sensing mechanism during photoluminescence study. H-bonding and photo-induced electron transfers (PET) are two plausible pathways for turn-on effect.

Electrostatic interaction, primarily hydrogen bonding between –OH and –COOH functional groups present on UiO-67 sensor with –N, -COOH and –F groups available on DANO analyte (Fig. 10) may cause fluorescence enhancement[19]. PL enhancement phenomenon for other FQs (CIPRO, NOR, LEVO, OFLO, LOME and DANO) is analogous to H-bonding on same mechanistic line but to different extents. Solely hydrogen bonding interaction is unable to explain thoroughly the observed enhancement behaviour. Collaborative PET procedure is introduced to explain PL enhancement phenomenon.

The E_HOMO-E_LUMO energies of FQs and BPDC ligands were calculated using Gaussian 09, B3LYP/6-311G set of software (Fig. 11). The turn-on fluorescence enhancement occurred due to migration of electrons from LUMO band of FQs to conduction band of UiO-67 in excited state because E_LUMO of FQs were higher than E_LUMO of BPDC ligand of UiO-67[20, 21]. Energy difference between LUMO of BPDC ligand (0.05436 a.u.) and LUMO of DANO (0.06053 a.u.) was lesser than that of other FQs, resulting in higher electron transfer rate from LUMO of DANO to LUMO of UiO-67. Both PET and H-bonding interaction process work cohesively to produce turn-on response.

3.4 Determinations of DANO in milk samples

Pasteurized milk was purchased from dairy booth located nearby Punjabi university, Patiala and spiked priorly with different concentrations of DANO antibiotic. 1 mL of every spiked milk sample was mixed with 2 mL acetonitrile and centrifuged to precipitate out proteins as solid substances. The centrifugation process was carried out for 6 min @ 5500 rpm. All supernatants were instantly collected into 5 mL volumetric flasks and diluted with deionized water to the mark. Resultant concentration of DANO in made-up samples ranged between 8.39 nM to 11.75 nM. PL spectra of MOF-DANO couples were recorded after addition of 0.1 mL UiO-67 MOF’s stock suspension to made-up samples bearing different concentrations of DANO (2.9 mL) under optimized conditions. Experiments were performed in triplicate. Recoveries were calculated and found to be from 96.3–103% with RSD value < 3.5% (Table 1).

Table 1

Comparative analysis of developed method
Sr. No.	Method	Matrix	LOD (ng/mL)	Recovery%	RSD%	Reference
1	HPLC-DAD	Water	0.02	90–110	< 6.3	[1]
2	Fluorescent probe Al(III)	Water	0.9	96.6–102.5	< 3	[3]
3	HPLC	Plasma	1	78–81	1.5(SD)	[22]
4	MLC − FD	Milk	0.5	93.5–104	< 4.4	[23]
5	HPLC-DAD	Methanol	5500	98–101.7	< 2.21	[24]
6	Electrochemical detection	Buffer	84.25	99.3–101.8	< 1	[25]
7	Fluorescent MOF (UiO-67)	Milk	0.49	95.2–101.2	< 2.5	Developed method

3.5 Comparative study

The sensitivity of developed UiO-67 fluorescent probe was compared with previously published methods (Table 2). Lower detection limit (0.49 ng/mL) was obtained in developed method. LOD reported by Lu et al is somewhat on lower side than present study [1], but former involved difficult MSPE approach for sample preparation. Magnetic nanocomposite preparational as well as preconcentration procedural steps make the whole process cumbersome and laborious. Prolonged detection durations from 2.8 to 11 min are limitations of chromatographic detection methods [22–24]. Developed method devoid of lengthy pre-treatment steps with rapid detection.

Table 2

Recoveries of DANO from spiked milk samples (n = 3)
Category	Amount spiked (nM)	Amount found (nM)	Recovery %	RSD %
Milk sample 1 (Fat 1.5%)	8.39	7.99	95.2	1.38
	8.95	8.60	96.1	1.25
	10.63	10.61	99.8	1.27
	11.75	11.60	98.7	0.78
Milk sample 2 (Fat 4.5%)	8.39	8.08	96.0	2.25
	8.95	8.94	99.9	1.06
	10.63	10.73	100.9	0.87
	11.75	11.73	99.8	1.34
Milk sample 3 (Fat 6%)	8.39	8.21	97.8	1.71
	8.95	9.03	100.9	1.62
	10.63	10.75	101.1	1.51
	11.75	11.48	97.7	1.43

Turn-on PL enhancement of MOF probes is successfully employed to create an efficient DANO sensing technique. UiO-67 MOF probe demonstrated its effectiveness as a sensor for DANO detection, with a limit of detection 1.37 nM (0.49 ng/mL) with superb enhancement efficiency and excellent stability upto third replicate cycle. The fluorescence ‘turn-on’ ability of the synthesized MOF probe is explained by hydrogen bonding and the PET mechanism, respectively. Sensing probe works with rapidity and high sensitivity. The procedure's precision, as well as accuracy, were tested by measuring DANO in spiked milk extracts at various concentrations. Excellent recoveries (95.2-101.1%) with RSD less than 2.5% validated the developed method’s high sensitivity. Method can be utilized as an instantaneous test for assessing the unmetabolized drug residues in milk after medical treatment of cattle with DANO antibiotics.

Author Contributions

Rajpal Verma, Gaurav Dhingra, Gurdeep Singh, Jaswinder Singh, Nidhi Dureja has performed the experiment and written the paper. Ashok Kumar Malik has edited the paper. All authors have reviewed the manuscript.

Funding

No funding was available supporting this research.

Competing Interests

“The authors have no relevant financial or non-financial interests to disclose.”

Data Availability

All relevant data will be provided on request.

Ethics approval

There is no ethical approval required.

Consent to participate

All authors have given consent to participate in publication process of this paper.

Consent to publish

All authors give consent to publish the paper.

Lu D, Qin M, Liu C et al (2021) Ionic liquid-functionalized magnetic metal–organic framework nanocomposites for efficient extraction and sensitive detection of fluoroquinolone antibiotics in environmental water. ACS Appl Mater Interfaces 13:5357–5367
Frade VMF, Dias M, Teixeira ACSC, Palma MSA (2014) Environmental contamination by fluoroquinolones. Brazilian J Pharm Sci 50:41–54
Kaur K, Saini S, Singh B, Malik AK (2012) Highly sensitive synchronous fluorescence measurement of danofloxacin in pharmaceutical and milk samples using aluminium (III) enhanced fluorescence. J Fluoresc 22:1407–1413
Vega D, Agüí L, González-Cortés A et al (2007) Voltammetry and amperometric detection of tetracyclines at multi-wall carbon nanotube modified electrodes. Anal Bioanal Chem 389:951–958
Evaggelopoulou EN, Samanidou VF (2013) HPLC confirmatory method development for the determination of seven quinolones in salmon tissue (Salmo salar L.) validated according to the European Union Decision 2002/657/EC. Food Chem 136:479–484
Alcaráz MR, Vera-Candioti L, Culzoni MJ, Goicoechea HC (2014) Ultrafast quantitation of six quinolones in water samples by second-order capillary electrophoresis data modeling with multivariate curve resolution–alternating least squares. Anal Bioanal Chem 406:2571–2580
Li Y-T, Qu L-L, Li D-W et al (2013) Rapid and sensitive in-situ detection of polar antibiotics in water using a disposable Ag–graphene sensor based on electrophoretic preconcentration and surface-enhanced Raman spectroscopy. Biosens Bioelectron 43:94–100
Mabeck JT, Malliaras GG (2006) Chemical and biological sensors based on organic thin-film transistors. Anal Bioanal Chem 384:343–353
Tan B, Zhao H, Du L et al (2016) A versatile fluorescent biosensor based on target-responsive graphene oxide hydrogel for antibiotic detection. Biosens Bioelectron 83:267–273
Dehghani S, Danesh NM, Ramezani M et al (2018) A label-free fluorescent aptasensor for detection of kanamycin based on dsDNA-capped mesoporous silica nanoparticles and Rhodamine B. Anal Chim Acta 1030:142–147
Zhou J-W, Zou X-M, Song S-H, Chen G-H (2018) Quantum dots applied to methodology on detection of pesticide and veterinary drug residues. J Agric Food Chem 66:1307–1319
Marimuthu M, Arumugam SS, Sabarinathan D et al (2021) Metal organic framework based fluorescence sensor for detection of antibiotics. Trends Food Sci Technol 116:1002–1028
Kumar P, Deep A, Kim K-H (2015) Metal organic frameworks for sensing applications. TrAC Trends Anal Chem 73:39–53
Liu D, Lu K, Poon C, Lin W (2014) Metal–organic frameworks as sensory materials and imaging agents. Inorg Chem 53:1916–1924
Liu S, Xu J, Dai E et al (2018) Synthesis and properties of ferrocene confined within UiO-67 MOFs. Microporous Mesoporous Mater 264:133–138
Zhang X, Zhang W, Li G et al (2020) A ratiometric fluorescent probe for determination of the anthrax biomarker 2, 6-pyridinedicarboxylic acid based on a terbium (III) – functionalized UIO-67 metal-organic framework. Microchim Acta 187:1–7
Han Y, He X, Yang W et al (2021) Ratiometric fluorescent sensing carbendazim in fruits and vegetables via its innate fluorescence coupling with UiO-67. Food Chem 345:128839
Bailey T, Pinto M, Hondow N, Wu K-J (2021) Continuous microfluidic synthesis of zirconium-based UiO-67 using a coiled flow invertor reactor. MethodsX 8:101246
Hua J, Jiao Y, Wang M, Yang Y (2018) Determination of norfloxacin or ciprofloxacin by carbon dots fluorescence enhancement using magnetic nanoparticles as adsorbent. Microchim Acta 185:1–9
Li C-P, Long W-W, Lei Z et al (2020) Anionic metal–organic framework as a unique turn-on fluorescent chemical sensor for ultra-sensitive detection of antibiotics. Chem Commun 56:12403–12406
Lustig WP, Mukherjee S, Rudd ND et al (2017) Metal–organic frameworks: functional luminescent and photonic materials for sensing applications. Chem Soc Rev 46:3242–3285
Garcia MA, Solans C, Aramayona JJ et al (2000) Development of a method for the determination of danofloxacin in plasma by HPLC with fluorescence detection. Biomed Chromatogr 14:89–92
Vílchez JL, Navalón A, Araujo L, Prieto A (2007) Determination of danofloxacin and marbofloxacin in milk samples by micellar liquid chromatography with fluorescence detection. Anal Lett 40:601–613
Hubicka U, Żuromska-Witek B, Żmudzki P et al (2014) Determination of danofloxacin and its photodegradation products by HPLC-DAD. Kinetic evaluation of the degradation process and identification of photoproducts by mass spectrometry. Anal Methods 6:2490–2498
El-Ries MA, Mohamed GG, Attia AK (2008) Electrochemical determination of veterinary drug danofloxacin. Sci Pap Univ Pardubice Ser A, Fac Chem Technol 13

No competing interests reported.

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You are reading this latest preprint version

Efficient turn-on Zr based metal organic framework fluorescent sensor for ultrafast detection of danofloxacin in milk samples

Status:

Journal Publication

Version 1

Abstract

Figures

Highlights

1. Introduction

2. Experimental

2.1. Materials and methods

2.2 Synthesis of UiO-67

3. Results and discussion

3.1 Characterization of UiO-67

3.1.1 FT-IR

3.1.2 PXRD

3.1.3 FE-SEM

3.1.4 EDX and elemental mapping

3.2 Photoluminescence study

3.2.1 Excitation wavelength

3.2.2 Solvent effect

3.2.3 pH effect and response time

3.2.4 Selectivity studies

3.2.5 Sensitivity studies

3.2.6 Interference study

3.2.7 Recyclability

3.3 Mechanistic study

3.4 Determinations of DANO in milk samples

3.5 Comparative study

4. Conclusion

Declarations

References

Additional Declarations

Supplementary Files

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